In areas of the world where there is snowfall, sleet, or heavy frost, a great amount of time, effort and money are spent every winter removing accumulated ice from various types of craft and equipment. This is most readily observed in connection with commercial and private aircraft. Ice must be removed from such craft before they can be safely used for air transportation.
The conventional technique for removing ice from the surfaces of aircraft is to spray the aircraft with heated ethylene glycol (antifreeze) compositions. This technique presents several problems and has associated drawbacks, including: (1) disposal problems because the antifreeze compositions can damage ground water supplies; (2) flammability problems due to inclusion of alcohol in the compositions; (3) damage to the skin of the aircraft caused by flying chunks of loosened, but not melted, ice; (4) turbine damage due to ingestion of the antifreeze; (5) the cost of purchasing, storing and heating the antifreeze compositions to the required temperatures; and (6) the cost and complexity of the equipment required to heat and apply the antifreeze to the skin of the aircraft.
There are also other types of equipment which must be cleared of accumulated ice before putting such equipment into use (e.g., spacecraft, rocket assemblies). In addition, it is also sometimes desirable to remove accumulated ice from other surfaces, e.g., heavy equipment, cranes, steel frameworks, and other surfaces where accumulated ice presents a problem or safety hazard.
It is an object of this invention to provide an improved technique and improved apparatus for melting ice from the surface of aircraft, spacecraft, rocket assemblies, and other surfaces.
It is another object of this invention to eliminate the problems associated with the conventional use of antifreeze compositions to remove accumulated ice.